lecture4 - Chem 120a 01/24/07 Spring 07 Dirac Notation:...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
Chem 120a Dirac Notation: Bras and Kets 01/24/07 Spring 07 Lecture 4 Reading: Feynman Chapter 1 and 3.1, 3.2 Last time, talked about quantum behaviors: P = | φ | 2 (1) (a) If 2 paths, φ = φ 1 + φ 2 , which plugging into (1) gives interference patterns (b) Along each path, φ = j j φ (c) if measure which path is taken, lose interference P = | φ 1 | 2 + | φ 2 | 2 Analyzing the decomposition of paths, we have: φ (y) = ii i1 , 2 ˆ ys s T|s s s = i , ˆ sT | s , i ss are all numbers representing probability amplitudes Æ this is an idealized analysis: we are assuming no medium, that is, nothing happens to the electron as it travels from the source s to the slit and then from the slit to the detector y. Æ if there is a medium, represent it with a generic operator ˆ Θ , i.e. i ˆ y| s Θ Nevertheless, in the ideal case, we have i ˆ | s i = T i = T = 1 and φ (y) = T , 2 = We have the completeness relation , 2 ss = = 1 φ (y) = 1 y , 2 = s = ys YAHOO!
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Bra-Kets in detail ab and ˆ a| b Θ are probability amplitudes s is a fundamental item called a ket It is a vector in complex vector space. ‘Physically’, it describes the state of the system we’re looking at
Background image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 3

lecture4 - Chem 120a 01/24/07 Spring 07 Dirac Notation:...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online